Powder coating matting agent comprising ester amide condensation product

ABSTRACT

The compounds of this invention are suitable matting agents for powder coatings. The compounds are ester amide-containing condensation products optionally comprising at least one β-hydroxyalkylamide functional group and, for example, are prepared from monomeric ester-amides, oligomeric polyester-amides or polymeric polyester-amides bearing β-hydroxyalkylamide groups by reacting the hydroxyalkylamide bearing ester amide with another compound such that at least one reactive functional group other than β-hydroxyalkylamide is also present on the condensation product, and further such that 50% or more of the terminal β-hydroxyalkylamide functionality has been reacted or converted to groups containing terminal carboxylic acid groups or other reactive groups including, but not limited to, groups reactive with polymers and crosslinkers suitable for preparing epoxy, epoxy-polyester, polyerster, polyester acrylic, polyester-primid, poylurethane or acrylic powder coatings. Other embodiments of the invention comprise the combination of the aforementioned condensation product with inorganic solids such as silicas and aluminas, and/or matte activators.

BACKGROUND

This invention relates to products suitable for use as a matting agentin powder coating formulations, and in particular condensation productscontaining at least one ester amide, optionally at least oneβ-hydroxyalkylamide group, and at least one reactive functional groupother than a β-hydroxyalkylamide.

Powder coatings, and in particular thermosetting powder coatings, arepart of a rapidly growing sector in the coatings industry. Thesecoatings are known for their glossy appearance and have the benefit ofnot containing volatile solvent.

Compounds containing β-hydroxyalkylamide groups have been disclosed inthe patent literature for purposes of preparing polymers andcrosslinkers for surface coatings. Particularly mentioned arewater-borne coatings and powder coatings. U.S. Pat. No. 4,076,917describes glossy powder coatings based on β-hydroxyalkylamide chemistry.

Primid XL552 from Rohm&Haas is an example of a β-hydroxyalkylamide-basedcrosslinker. It has been used with increasing success in curing carboxylbearing polyester-based resins to produce glossy powder coatings. Suchpowder coatings are generally intended for outdoor use. Compounds suchas Primid XL552 can be obtained by the reaction of di-esters ofcarboxylic acids with aminoalcohols such as those disclosed in U.S. Pat.No. 4,076,917. A typical example would be the dimethylester of adipicacid reacted with diethanolamine or disopropanolamine.

U.S. Pat. No. 3,709,858 refers to polyester-amide based coatingsprepared from polymers containing terminal and pendantβ-hydroxyalkylamide groups and also terminal and pendant carboxylicgroups for use in the preparation of coatings. Particularly mentionedare water-borne coatings, and the polymers can be considered as capableof self-curing at elevated temperatures. The polymers are obtained bycondensing polyols and polyacids and the β-hydroxyalkylamide chemistryarises from the use of N,N-bis[2-hydroxyalkyl]-2-hydroxyethoxyacetamideas a monomer. The polymers can be linear or branched.

In addition to the reaction products of saturated or unsaturatedmonomeric di-esters of carboxylic acids with aminoalcohols as monomericcrosslinkers for polymers bearing one or more carboxylic or anhydridefunctions, U.S. Pat. No. 4,076,917 further discloses polymers containingpendant β-hydroxyalkylamide groups as crosslinkers and self-curingpolymers containing both β-hydroxyalkylamide groups and carboxylic acidgroups. Acrylate based polymers were specifically discussed wherecopolymerization with β-hydroxyalkylamide compounds containing vinylgroups was performed. Patents relating to these latter aspects are U.S.Pat. No. 4,138,541; U.S. Pat. No. 4,115,637; and U.S. Pat. No.4,101,606. EP 322 834 describes powder coating compositions obtained bycrosslinkers of the type given in U.S. Pat. No. 4,076,917 withcarboxylic acid bearing polyester resins.

U.S. Pat. No. 5,589,126 discloses linear or branched amorphous orsemi-crystalline copolyesters of molecule weight between 300 and 15000containing two or more terminal β-hydroxyalkylamide groups for use ascrosslinkers with carboxylic acid bearing polymers such as are employedin powder coatings. Hydroxy numbers are between 10 and 400 mg KOH/g. Thepolymers are obtained by producing hydroxyl terminated polyesters,esterification with diesters of carboxylic acids and subsequent reactionwith aminoalcohols.

WO 99/16810 describes linear or branched polyester-amides having aweight average molecular weight of not less than 800 g/mol where atleast one amide group is in the polymer backbone and having at least oneterminal β-hydroxyalkylamide group. The polymers may be entirely orpartly modified with monomers, oligomers or polymers containing reactivegroups that can react with β-hydroxyalkylamide groups where crosslinkingis preferably avoided by using monomers, oligomers or polymers thatcontain only one group that can react with the β-hydroxyalkylamide groupe.g. monofunctional carboxylic acids. The polymers may be obtained byreaction of a cyclic anhydride with an aminoalcohol with subsequentpolycondensation between the resulting functional groups.

It is mentioned in WO 99/16810 that it is surprising that thepolyester-amides disclosed are capable of giving good flow and filmproperties in powder coatings because previous use of reactive polymershaving functionality greater than 6 in powder coatings are normallyassociated with poor appearance and poor film properties. The terminalβ-hydroxyalkylamide groups accordingly are modified to an extent lessthan 50% and preferably less than 30%.

WO 01/16213 describes a process to prepare polymers similar to thosedescribed in WO 99/16810, but that process involves reacting apolycarboxylic acid with an aminoalcohol followed by polycondensation inorder to produce a polymer employed as a crosslinker that does notrelease cyclic anhydrides when acid functional polyesters such as thoseused in powder coatings are cured.

The above references describe chemistries primarily designed to improvepowder coatings exhibiting glossy finishes and are for the most partsilent towards modifying those formulations to obtain flat or mattedfinishes. Indeed, there is considerable interest in matte powdercoatings which retain the good film properties of their glossycounterparts.

Solid particles such as silicas, carbonates and talcs are widely used tomatt conventional non-powder coatings. Matting conventional coatings,however, depends on the coating layer shrinking in thickness during filmformation due to solvent release or release of water in the case ofwater-borne coatings. An absence of such solvents and the accompanyingsignificant shrinkage renders this approach a relatively ineffectivemethod of matting powder coatings.

Waxes have also been used in matting agents for conventional coatingsand have on occasion been employed alone or in combination with fillersto reduce gloss in powder coatings. This approach, however, is not veryeffective and a greasy surface due to exudation of the wax can resultdepending on the extent the wax is incompatible with the polymericcomponent of the powder coating.

The limited success of conventional matting agents thus has led to thedevelopment of a number of new matting mechanisms for powder coatings.For example, it has been shown that powder coatings can be matted by (1)dry blending powders having different reactivity or flow capability, (2)co-extruding two powder coating compositions having different reactivityor even different reactive chemistry, (3) adding special curing agentshaving limited compatibility with the powder coating polymer, (4) use ofpolymer binders having a high degree of branching with reactiveend-groups, and (5) crosslinkers bearing two types of functional groupscapable of participating in reaction with polymers or polymer blendshaving different functional groups, each of which is reactive with oneor other of the functional groups associated with the crosslinker. Thelast two examples have been used with polyurethane powder coatings,while the first three mentioned have been used with epoxy,polyester-epoxy and polyurethane coatings. Matting of polyester powdercoatings tends to rely on the use of dry blends.

It is apparent that although low values of gloss below 20 at 60° can beobtained using current matting products or techniques in specificformulations of a given powder coating type, it has often been difficultto retain other desirable film properties such as flexibility, hardness,solvent resistance, outdoor durability and resistance to yellowingduring film cure. It is therefore an object of this invention to obtainmatting agents which can generate acceptable matte finishes, but at thesame time maintain other desirable film properties. It is also a goal toprovide a method in which conventional matting agents can still be usedin the matting agent, yet attain acceptable matte finishes, as well asmaintain those desirable film features mentioned above.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a method for making β-hydroxyalkylamide compounds andsubsequent reactions with a compound having functional groups other thanβ-hydroxyalkylamide for making a condensation product of this invention.

FIG. 2 illustrates an alternate process for preparing condensationproduct of this invention.

FIG. 3 illustrates viscoelastic data of a conventional polyester powdercoating during curing where the crosslinker is a conventionalhydroxyalkylamide crosslinker.

SUMMARY OF THE INVENTION

The compounds of this invention are ester amide-containing condensationproducts comprising, optionally, at least one β-hydroxyalkylamidefunctional group, and at least one reactive functional group other thana β-hydroxyalkylamide group. Such products can be prepared frommonomeric ester-amides, and linear or branched, oligomericpolyester-amides or polymeric polyester-amides. The condensation productof this invention, however, is reacted such that 50% or more of theterminal β-hydroxyalkylamide functionality has been converted to groupscontaining terminal or pendent carboxylic acid groups or other desirablefunctional groups with respect to the nature of the powder coating thatis to be matted. The total functionality is at least two functionalgroups (identical or different) per molecule.

Preferred functional groups of this invention comprise carboxylic acidgroups, or carboxylic acid groups in combination withβ-hydroxyalkylamide groups where the latter are present to an extent ofno more than 50% of the total functionality on a mole basis. Thesecompounds are compatible with and reactive with many types of polymerstypically employed in powder coatings. Given the reactivity of theβ-hydroxyalkylamide group, other reactive groups can be readilyintroduced depending on the specific powder coating to be matted. Otherreactive groups include, but are not limited to, those reactive withepoxy, polyester, epoxy-polyester, polyester-primid, polyurethane, andacrylic polymers which are employed as binders in typical powdercoatings.

Another embodiment of the invention comprises the combination of theaforementioned condensation product with inorganic solids such assilicas, aluminas, silicates and aluminosilicates. Such combinations canprovide additional control over the rheological processes occurringduring film formation, thereby leading to enhanced matting, easierhandling of the organic condensation product component from a health andsafety point of view and easier incorporation of the organic componentinto a powder coating in case the desirable organic component inquestion is liquid or semi-solid. Additionally, milling of the organiccomponent in the presence of an inorganic solid to a suitable particlesize can be more conveniently carried out, and the latter's use canresult in a product which can be incorporated into the powder coatingwith relative ease and uniformity.

Another embodiment comprises combining the condensation product with amatte activator, e.g., a suitable catalyst or coreactant for the powdercoating binder. These embodiments showed improved matting and filmproperties over those in which the condensation product is employedwithout, e.g., a catalyst or coreactant.

As indicated above, the condensation products of the invention areprepared by reacting an ester, or an ester-amide, bearing terminal orpendent β-hydroxyalkylamide groups, with another compound bearing theother reactive functional groups, or acting as a precursor to otherreactive functional groups, or acting as a precursor in the sense thatthe other reactive groups arise from further reactions which may includepolymerisation reactions. The two components, however, are reacted suchthat the gel point is not reached or exceeded during manufacture. It hasbeen found that when the total functionality or average number offunctional groups per molecule of the condensation product exceeds four,the product imparts a matting effect to powder coatings.

DETAILED DESCRIPTION

β-hydroxyalkylamide

The condensation product of this invention is prepared from compoundsbearing terminal β-hydroxyalkylamide groups. Ester-amide compoundsbearing terminal β-hydroxyalkylamide groups are in general known, e.g.,Primid® additives from Rhom & Haas, and examples of methods for makingsuch compounds are disclosed in U.S. Pat. Nos. 4,076,917; 3,709,858;U.S. Pat. No. 5,589,126 and WO 99/16810 the contents of which areincorporated herein by reference.

Thus, compounds bearing terminal β-hydroxyalkylamide groups can forexample be prepared from the reaction between (1) monomeric dialkylester derivatives of dicarboxylic acids and (2) β-aminoalcohols, whichmay in general be monoalkanolamines, dialkanolamines ortrialkanolamines.

In a variant of this method, oligomeric or polymeric substancescontaining on average two or more terminal ester groups can be used inplace of the monomeric diester. These oligomeric or polymeric speciesmay be obtained by transesterification of monomeric or polymeric polyolswith a suitable excess of a monomeric diester. Subsequent reaction ofthese oligomeric or polymeric species with a suitable aminoalcoholresults in a compound containing two or more β-hydroxyalkylamide groups.The actual number of groups will of course depend on whether amonoalkanolamine, a dialkanolamine or a trialkanolamine is used.

The species containing terminal ester groups may be replaced withderivatives of monomeric cyclic anhydrides or polyanhydrides. In thiscase, an addition reaction between the anhydride and aminoalcohol takesplace to produce a monomeric compound bearing carboxylic acid groups andβ-hydroxyalkylamide groups. In a further reaction step, this monomericcompound may be polymerised by a condensation reaction between thecarboxylic acid groups and β-hydroxyalkylamide groups to produce apolymeric compound bearing at least one terminal β-hydroxyalkylamidegroup. The number of β-hydroxyalkylamide groups remaining after such areaction depends on whether monoalkanolamines, dialkanolamines ortrialkanolamines are employed and also on whether the anhydride is amonoanhydride or a polyanhydride.

Whether obtained by the reaction of an ester with an aminoalcohol or ananhydride with an aminoalcohol, it is apparent that a compound bearingterminal β-hydroxyalkylamide groups may itself act as a polyol. It mayalso be reacted with a suitable excess of a monomeric diester to producespecies containing on average one or more terminal alkyl ester groupsfor further reaction with aminoalcohols.

Oligomeric or polymeric substances bearing ester groups mentioned aboveas suitable for manufacturing the hydroxyalkylamide compounds can beobtained by transesterification of monomeric alkyl esters of di- orpolyfunctional carboxylic acids with di- or polyfunctional alcohols ineither melt form or in solvent at a temperature in the range of 50° C.to 275° C. in the presence of suitable catalysts, such as, for example,metal carboxylates like zinc acetate, manganese acetate, magnesiumacetate or cobalt acetate as well as metal alkoxides like,tetraisopropyl titanate, or sodium methoxide.

Oligomeric or polymeric derivatives bearing terminal ester groups canalso be obtained by a conversion reaction of hydroxyl-functionalpolyesters with monomeric alkylesters of di- or polycarboxylic acids,either in melt form or in suitable solvents at a temperature in therange of 50° C. to 275° C. in the presence of suitable catalysts.

Hydroxyl-functional polyesters may be obtained by conventionalpolymerization techniques involving di- and polyfunctional carboxylicacids with di- and polyfunctional alcohols. Hydroxyl-functionalpolyesters with on average a higher degree of branching may be obtainedif required by polymerisation of suitable polyhydroxycarboxylic acidsaccording to methods described for example in U.S. Pat. No. 3,669,939,U.S. Pat. No. 5,136,014 and U.S. Pat. No. 5,418,301, the contents ofwhich are incorporated by reference.

Hydroxy-functional polyesters can also be prepared via esterificationand ester interchange reactions or via ester interchange reactions.Suitable catalysts for those reactions include, as an example, dibutyltin oxide or titanium tetrabutylate.

Suitable hydroxy-functional polyester resins have a hydroxyl value of10-500 mg KOH/g.

The monomeric alkyldiesters of polycarboxylic acids indicated in theabove reactions include dimethyl terephthalate, dimethyl adipate anddimethylhexahydroteraphthalate.

Examples of suitable di- and polyfunctional carboxylic acid componentsin the above reactions include, but are not limited to, aromaticmulti-basic carboxylic acids such as terephthalic acid, isophthalicacid, phthalic acid, pyromellitic acid, trimellitic acid,3,6-dichlorophthalic acid, tetrachlorophathalic acid, and theiranhydride, chloride or ester derivatives, together with aliphatic and/orcycloaliphatic multi-basic acids such for example as1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid,hexahydroendomethylene terephthalic acid, hexachlordphthalic acid,C₄-C₂₀ dicarboxylic acids such as, for example, azelaic acid, sebacicacid, decandicarboxylic acid, adipic acid, dodecandicarboxylic acid,succinic acid, maleic acid, as well as dimeric fatty acids and theiranyhdride, chloride and ester derivatives. Hydroxycarboxylic acidsand/or lactones such as, for example, 12-hydroxystearic acid,epsilon-Caprolacton or hydroxypivalic acid ester of neopentyl glycol,can likewise be used. Monocarboxylic acids, such as, for example,benzoic acid, tertiary butylbenzoic acid, hexahydrobenzoic acid andsaturated aliphatic monocarboxylic acids may also be used as required.

The following aliphatic diols are named by way of example of suitabledifunctional alcohols mentioned above: ethylene glycol, 1,3-propanediol,1,2propanediol, 1,2butanediol, 1,3-butanediol, 1,4butanediol,2,2-dimethylpropane1,3-diol (neopentyl glycol), 2,5-hexandiol,1,6-hexandiol, 2,2-[bis-(4hydroxycyclohexyl)]propane,1,4dimethylolcyclohexane, diethylene glycol, dipropylene glycol and2,2-bis-[4-(2-hydroxy)]phenyl propane.

Suitable polyfunctional alcohols mentioned above are glycerol,hexanetriol, pentaeryltritol, sorbitol, trimethylolethane,trimethylolpropane and tris(2-hydroxy)isocyanurate. Epoxy compounds canbe used instead of diols or polyols. Alkoxylated diols and polyols arealso suitable.

2,2-bis-(hydroxymethyl)-propionic acid, 2,2-bis-(hydroxymethyl)-butyricacid, 2,2-bis-(hydroxymethyl)-valeric acid,2,2,2-tris-(hydroxymethyl)-acetic acid and 3,5.dihydroxybenzoic acid maybe mentioned as examples of polyhydroxylcarboxylic acids.

In all of the above, previously prepared compounds containing terminalβ-hydroxyalkylamide groups may also be employed instead of or inaddition to the above mentioned di- and polyfunctional alcohols.

In all of the above, mixtures of various polyols, polybasic carboxylicacids and hydroxyl- and polyhydroxylcarboxylic acids or mixtures oftheir corresponding oligomers or polymers and their corresponding esterterminated analogues can be used.

In the above, the ratio of ester groups to hydroxyl groups in theconversion reaction between the diester and the hydroxyl bearingsubstance varies with the nature of the polyol, its functionality, thedesired material and the need to avoid gelation. If for example theaverage functionality of the polyol is three, the minimum proportion ofpolyol to diester is such that the ratio of hydroxyl to ester groups is0.5. If the average functionality of the polyol is six, the minimumproportion of polyol to diester is such that the ratio of hydroxyl toester groups is 0.3

As mentioned above, derivatives of monomeric cyclic anhydrides orpolyanhydrides can be used instead of diester derivatives to prepare the-hydroxylalkylamide compound.

A preferable cyclic anhydride is a mono anhydride according to formulaI:

in which A has the meaning specified later below.

Examples of suitable cyclic anhydrides include phthalic anhydride,tetrahydrophthalic anhydride, naphtalenic dicarboxylic anhydride,hexahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride,norbornene-2,3-dicarboxylic anhydride, naphtalenic dicarboxylicanhydride, 2-dodecene-1-yl-succinic anhydride, maleic anhydride,(methyl)succinic anhydride, glutaric anhydride, 4-methylphthalicanhydride, 4-methylhexahydrophthalic anhydride,4-methyltetrahydrophthalic anhydride and the maleinised alkylester of anunsaturated fatty acid.

Preferably the aminoalcohol reactive with the ester or anhydride is acompound according to the Formula II:

in which:

R¹, R², R³, and R⁴ may, independently of one another, be the same ordifferent, and includes, but is not limited to, H, or substituted orunsubstituted alkyl (linear or branched), (C₆-C₁₀) aryl(C₁-C₂₀)(cyclo)alkyl radical. Generally n=1-4, but more preferably, n=1.

The aminoalcohol may be a monoalkanolamine, a dialkanolamine, atrialkanolamine or a mixture hereof.

Dialkanolamines are preferred, but if monoalkanolamines are used in thereaction with cyclic anhydrides, in order to obtain polymers bearingβ-hydroxyalkylamide groups with a functionality of 2 or greater,polyanhydrides would need to be employed so as to provide sufficientfunctionality to produce a final product having the desiredfunctionality. Similarly, if monoalkanolamines are employed in thereaction with oligomeric or polymeric substances bearing ester groups,the substances would need an average functionality of at least two estergroups to produce polymers bearing β-hydroxyalkylamide groups with afunctionality of 2 or greater.

If a highly branched structure with relatively high functionality isdesired, di- or trialkanolamines can be used.

Overall therefore, depending on the application desired, a linear or anentirely or partly branched oligomer or polymer bearingβ-hydroxyalkylamide groups can be chosen, in which further moderation ofthe structure can be attained via the alkanolamines selected forpreparation of the desired oligomer or polymer.

Examples of suitable mono-o-alkanolamines include2-aminoethanol(ethanolamine), 2-(methylamino)-ethanol,2-(ethylamino)-ethanol, 2-(butylamino)-ethanol, 1-methylethanolamine(isopropanolamine), 1-ethyl ethanolamine, 1-(m)ethylisopropanolamine, n-butylethanolamine, β-cyclohexanolamine, n-butylisopropanolamineand 2-Amino-1-propanol,.

Examples of suitable di-o-alkanolamines are diethanolamine(2,2′-iminodiethanol), 3-amino-1,2-propanediol, 2-amino-1,3-propanediol,diisobutanolamine (bis-2-hydroxy-1-butyl)amine), di-β-cyclohexanolamineand diisopropanolamine(bis-2-hydroxy-1-propyl)amine).

A suitable trialkanolamine is, for example,tris(hydroxymethyl)aminomethane.

In a number of instances, alkanolamines with β-alkyl-substitution arepreferably used. Examples are (di)isopropanolamine, cyclohexylisopropanolamine, 1-(m)ethyl isopropanolamine, (di)isobutanolamine,di-β-cyclohexanolamine and/or n-butyl isopropanolamine.

The ester:alkanolamine amine equivalent ratio is generally, in the rangeof 1:0.5 to 1:1.5 and more typically in the range of 1:0.8 to 1:1.2.

The anhydride:aminoalcohol equivalent ratio is dependent upon theanhydride, but generally is between 1.0:1.0 and 1.0:1.8. Preferably,this ratio is between 1:1.05 and 1:1.5.

When an anhydride is reacted with an aminoalcohol, the reaction can becarried out by reacting the anhydride and aminoalcohol at a temperaturebetween, for example, about 20° C. and about 100° C., to form asubstantially monomeric hydroxyalkylamide, after which, at a temperaturebetween, for example, 120° C. and 250° C., a polyesteramide is obtainedthrough polycondensation with water being removed through distillation.

Excess aminoalcohol may be required when employing this procedure toregulate molecular weight build-up. Alternatively, use of amonofunctional β-hydroxyalkylamide group containing compound ormonofunctional carboxylic acid compound to moderate the functionalitymay be employed depending on the final compound desired. A furthermoderating procedure, which may be used separately or in combinationwith the previously mentioned options is to employ a compound containing2 or more β-hydroxyalkylamide groups, but no other reactive groupcapable of reacting with a β-hydroxyalkylamide group. These are similartechniques to those employed to prepare polyesters with terminalhydroxyl groups with varying degrees of branching such as is for exampledescribed in U.S. Pat. No. 5,418,301, the contents of which areincorporated by reference.

When an ester containing compound is reacted with an aminoalcohol, thereaction can be carried out at a temperature between 20° C. and 200° C.,more typically 80° C. to 120° C., optionally in the presence of suitablecatalysts such as metal hydroxides, metal alkoxides, quaternary ammoniumhydroxides and quaternary phosphonium compounds. The alcohol arisingfrom the reaction is removed by distillation. The proportion of catalystmay typically range from 0.1% to 2% by weight.

The reactions can take place in a melt phase, but also in water or in anorganic solvent.

The removal of water or alcohol through distillation can take place at apressure higher than 1 bar, under reduced pressure, azeotropically undernormal conditions of pressure, with co-distillation of solvent or withthe aid of a gas flow.

Using derivatives discussed above, specific β-hydroxyalkylamidesaccording to the Formula (III) below can be prepared:

wherein A is a bond, hydrogen or a monovalent or polyvalent organicradical derived from a saturated or unsaturated alkyl radical whereinthe alkyl radical contains from 1-60 carbon atoms, such as methyl,ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl,eicosyl, triacontyl, tetracontyl, pentacontyl, hexylcontyl and the like;substituted or unsubstituted aryl, for example, C₂-C₂₄ mono- anddinuclear aryl such as phenyl, naphthyl and the like; C₁-C₈ cycloalkyl,diradical, tri-lower alkyleneamino such as trimethyleneamino,triethyleneamino and the like; or an unsaturated radical containing oneor more ethylenic groups [>C═C<] such as ethenyl, 1-methylethenyl,3-butenyl-1,3-diyl, 2-propenyl-1,2-diyl, carboxy lower alkenyl, such as3-carboxy-2-propenyl and the like; lower alkoxy carbonyl lower alkenylsuch as 3-methoxycarbonyl-2-propenyl and the like.

R⁵ is hydrogen, alkyl, preferably of from 1-5 carbon atoms such asmethyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, pentyl and thelike or hydroxy lower alkyl preferably of from 1-5 carbon atoms such ashydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl,3-hydroxybutyl, 2-hydroxy-2-methylpropyl, 5-hydroxypentyl,4-hydroxypentyl, 3-hydroxypentyl, 2-hydroxypentyl and the isomers ofpentyl; R⁵ can also be Y in Formula II above.

R¹, R², R³ and R⁴ preferably are the same or different radicals selectedfrom hydrogen, straight or branched chain alkyl, preferably of from 1-5carbon atoms, or R¹ and R³ or R² and R⁴ radicals may be joined to form,together with the carbon atoms, a C₃-C₂₀ such as cyclopentyl, cyclohexyland the like; m is an integer having a value of 1 to 4; n is an integerhaving a value of 1 or 2 and n′ is an integer having a value of 0 to 2.When n′ is 0, A can be a polymer or copolymer (i.e., n has a valuegreater than 1 preferably 2-12) formed from the β-hydroxyalkylamide whenA is an unsaturated radical.

More specific compounds are those of the foregoing Formula III, whereinR⁵ is H, lower alkyl, or HO(R³)(R⁴)C(R¹)(R²)C—, n and n′ are each 1, -A-is —(CH₂)_(m)—, m is 0-8, preferably 2-8, each R group is H, and one ofR³ or R⁴ radicals in each case is H and the other is H or a C₁-C₅ alkyl;that is, of formula (IV)

(wherein R⁵, R³, and m have the meanings given above.

Specific examples falling within Formula II arebis[N,N-di(β-hydroxyethyl)]adipamide,bis[N,N-di(β-hydroxypropyl)]succinamide,bis[N,N-di(β-hydroxyethyl)]azelamide,bis[N-N-di(β-hydroxypropyl)]adipamide, andbis[N-methyl-N-(βhydroxyethyl)]oxamide. A method for making a suitablehydroxyalkylamide is illustrated in FIG. 1.

Specific β-hydroxyalkylamides also are those of the foregoing FormulaIII where A is a polyester polymer chain which is either linear orbranched, where optionally the chain contains ester-amide groups.Accordingly, A can additionally comprise ester amides alternating alonga polymeric backbone, or in the case of a branched structure, the esterand amide linkages alternate among the main and side chains of thebranched structure.

Other Reactive Functional Group

The β-hydroxyalkylamide selected and/or prepared is then reacted with acompound bearing functional groups or precursors to functional groupsother than a hydroxyalkylamide group. That compound is a monomer,oligomer or polymer which in addition to the group which is not ahydroxyalkylamide, contains at least one functional group that can reactwith a hydroxyalkylamide group. In some cases, the compound bearing thefunctional groups or precursors to functional groups may after reactionwith a suitable hydroxyalkylamide compound be subject to polymerisationto produce the final condensation product bearing the desired functionalgroups.

Compounds bearing such functional groups or precursors to suchfunctional groups include cyclic anhydrides, monomeric or polymericpolycarboxylic acids or polycarboxylic acid anhydrides containing one ormore anhydride groups per molecule and one or more free carboxylic acidgroups per molecule, which after reaction with the β-hydroxyalkylamide,results in free carboxylic acid groups remaining. Specific examples ofcarboxylic acids and anhydrides include, but are not limited to, adipicacid, decanedicarboxylic acid, trimellitic anhydride, phthalic acid orphthalic anhydride, tetrahydrophthalic acid or tetrahydrophthalicanhydride, hexahydrophthalic acid, tetrahydrophthalic anhydride,tetrahydrophthalic acid, hexahydrophthalic anhydride, pyromellitic acid,pyromellitic anhydride, 3,3′,4,4′-tetra-benzophenone carboxylic acidanhydride and combinations thereof.

Other suitable carboxylic acid compounds are, for example, dimer ortrimer acids of saturated aliphatic (C₁-C₂₆) acids, unsaturated (C₁-C₃₆)fatty acids, hydroxycarboxylic acids and polyhydroxycarboxylic acidssuch as 2,2-bis-(hydroxymethyl)-propionic acid as well asα,β-unsaturated acids.

Examples of suitable α,β-unsaturated acids are (meth)acrylic acid,crotonic acid and monoesters or monoamides of itaconic acid, maleicacid, 12-hydroxystearic acid, polyether carboxylic acid, and fumaricacid.

When polycarboxylic acids are used, the functional groups on the finalcondensation product of this invention would be predominantly freecarboxylic acid groups. The use of cyclic anhydrides or polycarboxylicacid anhydrides on the other hand allows selective reaction of theanhydride groups with the β-hydroxyalkylamide groups under conditionssuch that the free carboxylic acid groups are substantially unreactive.In this way, compounds containing both types of groups can be prepared.FIG. 2 illustrates a method for making the final ester-amidecondensation product of the invention using anhydrides.

Examples of other suitable reactive groups include, but are not limitedto, isocyanate groups, epoxy groups, alkoxysilane groups, acid chloridegroups, epoxychlorohydrine groups, amine groups, phenolic groups,methylolated amide groups, hydroxyl groups, methylol groups andcombinations hereof.

Examples of suitable isocyanates include, but are not limited to,diisocyanates such as 1,4-diisocyanato-4-methyl-pentane,1,5-diisocyanato-5-methylhexane,3(4)-isocyanatomethyl-1-methylcyclohexylisocyanate,1,6-diisocyanato-6-methylheptane, 1,5-diisocyanato-2,2,5-trimethylhexaneand 1,7-diisocyanato-3,7-dimethyloctane, and1-isocyanato-1-methyl-4-(4-isocyanatobut-2-yl)-cyclophexane,1-isocyanato-1,2,2-trimethyl-3-(2-isocyanato-ethyl)-cyclopentane,1-isocyanato-1,4-dimethyl-4-isocyanatomethyl-cyclohexane,1-isocyanato-1,3-dimethyl-3-isocyanatomethyl-cyclohexane,1-isocyanatol-n-butyl-3-(4-isocyanatobut-1-yl)-cyclopentane and1-isocyanato-1,2dimethyl-3-ethyl-3-isocyanatomethyl-cyclopentane,respectively.

In the event oligomeric or polymeric esters are used to prepare theβ-hydroxyalkylamide compound, such derivatives may be reacted withcyclic anhydrides, polycarboxylic acids or polycarboxylic acidanhydrides just as when using monomeric esters.

In the event the initially formed β-hydroxyalkylamide compound containsmore than two β-hydroxyalkylamide groups per molecule, one or more suchgroups can be blocked by reaction with a suitable monofunctional reagentsuch as a monofunctional carboxylic acid prior to reaction with apolycarboxylic acid or a polycarboxylic acid anhydride or otherdesirable reactive groups.

Thus, the methods essentially involve preparing a monomeric ester-amide,or an oligomeric or polymeric ester-amide of non-linear structure withterminal β-hydroxyalkylamide groups and subsequently reacting at least50%, of those terminal groups with cyclic anhydrides, polycarboxylicacids, polycarboxylic acid anhydrides, or other suitable compounds asdescribed above depending on the desired structure and functional group,where the various reactions may be carried out in one or more stepsaccording to well known polymerization and sequential functionalizationtechniques.

Condensation Product

In general, the average number (mole basis) of desired functional groupsper molecule or “functionality” present in the condensation product ofthis invention after reacting the β-hydroxyalkylamide with, for example,cyclic anhydrides, can range from 4 to 48, preferably at least 8, andmore preferably in the range of 8-24 functional groups per molecule, butwhereby not more than 50% of the total number of functional groups permolecule are β-hydroxyalkylamide groups. In other words, at least fiftypercent of the functional groups (on a mole basis) are groups other thana β-hydroxyalkylamide group. Desired functional group content by weightranges from 50 to 750 mgKOH/g.

The number average molecular weight of the final condensation productranges from 300 to 15,000, preferably 1000-5000.

As indicated earlier, the reactive functional groups on the finalmolecule of the condensation product are selected depending on theparticular polymer binder of the powder coating in which the productwill be added as a matting agent. The binders typically used in powdercoatings include, but are not limited to, epoxy-polyesters, epoxies,polyesters, polyester-acrylics, polyester-primids, polyurethane, andacrylics. Epoxy-polyesters are frequently used binders, and carboxylicfunctionality would be a preferred reactive functional group for amatting agent intended for such binders.

The condensation product may be prepared in the melt phase, or may beprepared in a suitable organic solvent, for example an aprotic solventsuch as dimethylacetamide or N-methyl-2-pyrrolidone.

Solvents such as N-methyl-2-pyrrolidone can subsequently be removed bydistillation. However, due to the high boiling point and high heat ofvaporization, large amounts of energy would be needed for thisoperation. Moreover, it is usually difficult to ensure substantiallycomplete removal of such solvents in this way due to the stronginteractions existing between the solvent and the solute. An alternativemethod is to extract the solvent into a second solvent such that thesolute is not soluble in the solvent mixture. A suitable second solventin many of the present cases is water, but may for example also bealcohols or water-alcohol mixtures. Further counter-current washing ofthe precipitated product with water or the second solvent may be carriedout as necessary to ensure substantial removal of the first solvent.

The solvent solution of the product may be added under intense stirringto the second solvent, for example as droplets or as a continuous streamof material such that the precipitated product is present substantiallyin a particulate form. In some cases, this process may be aided by thepresence of an inorganic solid. This is particularly helpful, if theprecipitated organic product does not have a solid-like character. Theresulting product may finally be dried at temperatures not exceeding100° C.

Drying at temperatures above the glass transition temperature of thecondensation product can lead to the product flowing and binding anyinorganic components that may be present, resulting in bondedagglomerates. In this form, the condensation product may not readilydissolve in otherwise suitable solvents and may not readily dispersethroughout the powder coating during extrusion. With certain embodimentsit may be preferable to obtain the condensation product in the purestate (without inorganic particulate) by the above method of solventextraction. In this case, the particulate form resulting from theprocedure may be lost if the drying temperature is too high.

In order to avoid these problems, when the product is dried it ispreferable to dry it under reduced pressure. This may for example becarried out in a vacuum oven or in a rotational evaporator equipped withfacilities for application of a vacuum. A final rinse with a volatilewater miscible solvent such as acetone, methyl ethyl ketone, methanol,ethanol or isopropanol after water washing such that the final solventdoes not dissolve the organic component may be carried out prior todrying. Alternatively, the product may be reslurried/redissolved insolvents such as acetone, methyl ethyl ketone, methanol, ethanol orisopropanol, in water or in combinations thereof and the productrecovered by drying.

Either of the above problems may also be avoided by spray drying asolution of product together with an inorganic solid if desired in orderto obtain a final product having a suitable particulate form. Suitablesolvents may for example be selected from alcohols, water/alcoholmixtures and ketones.

The overall approach therefore avoids high temperatures that wouldotherwise make it difficult to prepare compounds containing two or moretypes of functional groups that are reactable with one another. Anyesterification and transesterification catalysts that are used duringthe chemical reactions leading to the final product can also beextracted to the extent that they are soluble in the second solvent andto the extent that their removal is desirable.

Where the condensation product is prepared entirely in the melt phase,obtaining the product in a suitable particulate form for incorporationinto the powder coating could be achieved by the techniques mentionedabove. For example, the melt could be run into a stirred non-organicsolvent such as water, or the-material could be dissolved in a suitablesolvent and the resulting solution spray dried. However, the moststraightforward procedure would be to cool the product and to simplypulverize the solidified material to a suitable particle size.

In an alternative procedure, it may be possible in some cases to blendthe reagents together in an aqueous or organic solvent phase includingany inorganic solid to be present in the final product as required, drythe resultant mixture and complete any remaining reaction orpolymerization steps in the solid state.

Where the condensation product is to be combined with a matte activator,described below, the matte activator may be added at any suitable stepin the above reaction and processing sequence. Typically, the matteactivator is added during the slurrying or redissolution steps thatprecede drying.

In any of the above instances, a suitable average particle size for thefinal matting agent product in order to facilitate it into the finalpowder coating mixture is regarded as ranging from about 1 μm to about100 μm and preferably not greater than 50 μm. The final product maysubsequently be pulverized or milled if required. Any final milling stepshould be carried out at suitably low temperatures in the event onlycondensation product is in the final matting agent product.

The amount of condensation product added to the powder coating dependson the amounts of other additives included in the powder formulation,e.g., other additives such as a matte activator and other optionaladditives discussed below. In general, the amounts of condensationproduct to be added can range from about 0.5% to 20% based on the totalweight of the powder coating formulation. Preferably the amount rangesfrom about 1% to 10% based on the weight of binder in the powder coatingformulation.

A mixture of different condensation products, each falling within thescope of the invention may also be employed in the powder coatingformulation.

In certain stances, it is also suitable to combine the invention withβ-hydroxyalkylamides containing more than 50% β-hydroxyalkylamidefunctionality insofar as the overall active functionality of thecombination comprises no more than 50% β-hydroxyalkylamide.

Inorganic Particulate Additives

Inorganic particulates suitable for incorporation with the condensationproduct include those inorganic-based matting agents employed inconventional solvent borne coatings.

Silica particulates are suitable. These particulates range in averageparticle size from 1 to 20 microns, preferably 5 to 10 microns. Poroussilicas are usually preferred for their matting efficiency and have porevolumes ranging from 0.5 to 2.0 cc/g, preferably 1.0 to 2.0 cc/g.Particle sizes mentioned above are those reported using a CoulterCounter and the pore volume is that obtained using nitrogen porosimetry.Suitable silicas and methods for making them are described in U.S. Pat.No. 4,097,302, the contents of which are incorporated by reference.Particulated aluminum oxide or metal silicates and aluminosilicates inthe size ranges above are also suitable.

Inorganic particulates can be present in a range of 0 to 2 parts byweight per one part by weight condensation product. Embodimentscontaining such particulates, however, more typically contain inorganicparticulate and condensation product at a ratio of 1:1 parts by weight.

If an inorganic particulate is to be present in the final mattingcompound together with the condensation, dry-blending or co-milling thetwo after preparation of the condensation product in particulate formcan be carried out. The inorganic component such as a silica or aluminacan, if dry, be added at any stage of the reaction sequences leading tothe condensation product. As mentioned above, the inorganic componentmay also be added to the reaction product just prior to a precipitationstep, or may be added to a solution or slurry of the condensationproduct just prior to the final drying step. Where an inorganiccomponent is to be added during the reaction sequences leading to thecondensation product, or added prior to precipitation or drying steps,the presence of a solvent or carrier medium such as those mentionedearlier may, for rheological reasons be helpful.

The final product may subsequently be pulverized or milled as required.The final product should be milled to that having an average particlesize suitable for facilitating it into the final powdered coatingmixture. Suitable average particle sizes for the final matting agentproduct range from about 1 μm to about 50 μm.

Matte Activator

As indicated above, matte activators may also be used in combinationwith condensation product of this invention to prepare a preferredmatting agent. A matte activator includes, but is not limited to,compounds such as catalysts or coreactants known in the art. Theseactivators accelerate or facilitate matting, facilitate curing of thepowder coating to which the invention is added and promote formation offilms having the desired properties. The selected activator depends onthe binder in the powder coating. A catalyst suitable as an activatorhereunder can be defined as a compound left unchanged after the reactionof the invention and powder coating binder and is usually used inrelatively small amounts. A coreactant suitable hereunder, which may bepresent in varying amounts, is used up as it participates and is usuallyconsumed in the aforementioned reaction. Quaternary phosphonium halidesand quaternary phosphonium phenoxides and carboxylates such as thosedescribed in EP 019 852 or U.S. Pat. No. 4,048,141, the contents ofwhich are incorporated herein by reference, are particularly suitablematte activators.

Preferred phosphonium-based matte activators are represented by theformula (V):

wherein each R is independently a hydrocarbyl or inertly substitutedhydrocarbyl group, Z is a hydrocarbyl or inertly substituted hydrocarbylgroup and X is any suitable anion.

The term “hydrocarbyl” as employed herein means any aliphatic,cycloaliphatic, aromatic, or aliphatic or cycloaliphatic substitutedaromatic groups. The aliphatic groups can be saturated or unsaturated.Those R groups which are not aromatic contain from 1 to 20, preferablyfrom 1 to 10, more preferably from 1 to 4 carbon atoms.

The term “inertly substituted hydrocarbyl group” means that thehydrocarbyl group can contain one or more substituent groups that doesnot enter into the reaction and does not interfere with the reactionbetween the epoxy compound and the polyester. Suitable such substituentgroups include for example, NO₂, Br, Cl, I, F.

Suitable anions include, but are not limited to, halides such as, forexample, chloride, bromide, iodide and the carboxylates as well as thecarboxylic acid complexes thereof, such as formate, acetate, propionate,oxalate, trifluoroacetate, formateformic acid complex, acetateaceticacid complex, propionatepropionic acid complex, oxalateoxalic acidcomplex, trifluoroacetatetrifluoroacetic acid complex. Other suitableanions include, for example, phosphate, and the conjugate bases ofinorganic acids, such as, for example, bicarbonate, phosphate,tetrafluoroborate or biphosphate and conjugate bases of phenol, such as,for example phenate or an anion derived from bisphenol A.

Some of the catalysts are commercially available; however, those whichare not can be readily prepared by the method described by Dante et al.in the aforementioned U.S. Pat. No. 3,477,990, by Marshall in theaforementioned U.S. Pat. No. 4,634,757 and by Pham et al. in theaforementioned U.S. Pat. No. 4,933,420. Examples of the above-mentionedphosphonium catalysts include, among others, methyltriphenylphosphoniumiodide, ethyltriphenylphosphonium iodide, propyltriphenylphosphoniumiodide, tetrabutylphosphonium iodide, methyltriphenylphosphoniumacetateacetic acid complex, ethyltriphenylphosphonium acetateacetic acidcomplex, propyltriphenylphosphonium acetateacetic acid complex,tetrabutylphosphonium acetateacetic acid complex,methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide,propyltriphenylphosphonium bromide, tetrabutylphosphonium bromide,ethyltriphenylphosphonium phosphate, benzyl-tri-para-tolylphosphoniumchloride, benzyl-tri-para-tolylphosphonium bromide,benzyl-tri-para-tolylphosphonium iodide,benzyl-tri-meta-tolylphosphonium chloride,benzyl-tri-meta-tolylphosphonium bromide,benzyl-tri-meta-tolylphosphonium iodide,benzyl-tri-ortho-tolylphosphonium chloride,benzyl-tri-ortho-tolylphosphonium bromide,benzyl-tri-ortho-tolylphosphonium iodide, tetramethylene bis(triphenylphosphonium chloride), tetramethylene bis(triphenyl phosphoniumbromide), tetramethylene bis(triphenyl phosphonium iodide),pentamethylene bis(triphenyl phosphonium chloride), pentamethylenebis(triphenyl phosphonium bromide), pentamethylene bis(triphenylphosphonium iodide), hexamethylene bis(triphenyl phosphonium chloride),hexamethylene bis(triphenyl phosphonium bromide), hexamethylenebis(triphenyl phosphonium iodide), or any combination thereof.

Particularly suitable phosphonium compounds which can be employed hereininclude, for example, methyltriphenylphosphonium iodide,ethyltriphenylphosphonium iodide, tetrabutylphosphonium iodide,methlytriphenylphosphonium acetateacetic acid complex,ethyltriphenylphosphonium acetateacetic acid complex,tetrabutylphosphonium acetateacetic acid complex,methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide,tetrabutylphosphonium bromide, ethyltriphenylphosphonium phosphate,benzyl-tri-para-tolylphosphonium chloride,benzyl-tri-para-tolylphosphonium bromide,benzyl-tri-para-tolylphosphonium iodide,benzyl-tri-meta-tolylphosphonium chloride,benzyl-tri-meta-tolylphosphonium bromide,benzyl-tri-meta-tolylphosphonium iodide,benzyl-tri-ortho-tolylphosphonium chloride,benzyl-tri-ortho-tolylphosphonium bromide,benzyl-tri-ortho-tolylphosphonium iodide or any combination thereof.

Tertiary amine and quaternary ammonium halide catalysts are suitablewhen preparing matting agents for powder coatings involving the reactionof an epoxy group and a carboxylic group containing compound.

Esterification and transesterification catalysts such as metal alkoxidesand metal carboxylates are suitable for use with matting agents of thisinvention designed for polyester primid coatings.

As indicated above, it has been discovered that these substances enhancethe degree of matting attained at a given addition level of mattingagent. Typically the matte activator would be added by blending one ormore, e.g., catalyst and/or coreactants with the final condensationproduct. That would generally require adding by weight of thecondensation product, 1 to 50% and more typically 5 to 33% of catalystor co-reactant , i.e., a ratio of condensation product to catalystand/or co-reactant of 100:1 to 1:1 and more typically 20:1 to 2.1. Aratio of condensation product to catalyst and/or co-reactant ofapproximately 4:1 to 6:1 is preferred.

Accordingly a preferred embodiment of the inventive product comprises(1) an ester amide condensation product described above, and (2) aninorganic solid and/or matte activator compound.

Other Optional Additives

If so desired, additives such as those used in conventional powdercoatings can be combined with the condensation product according to theinvention. Such additives include, for example, pigments, fillers,degassing agents, flow agents and stabilizers. Suitable pigments are forexample inorganic pigments, such as for example titanium dioxide, zincsulphide, iron oxide and chromium oxide, and also organic pigments suchas for example azo compounds and phthalocyanine compounds. Suitablefillers are for example metal oxides, silicates, carbonates andsulphates.

Primary and/or secondary antioxidants, UV stabilizers such as quinones,(sterically hindered) phenolic compounds, phosphonites, phosphites,thioethers and HALS compounds (hindered amine light stabilizers) can forexample be used as stabilizers.

Examples of degassing agents are benzoin and cyclohexane dimethanolbisbenzoate. The flow agents include for example polyalkylacrylates,polyvinyl acetyls, polyethyleneoxides, polyethyleneoxide/propyleneoxidecopolymers, fluorohydrocarbons and silicone fluids.

Any optional additives and the condensation product can then be blendedinto the powder coating mixture using conventional means. The finalmatting agent composition can be incorporated as a dry blend with thepowder coating binder, or it can be combined with those binders in, forexample an extruder, to form particles containing binder, matting agentand any other additive introduced into the extruder.

Matting Mechanism

Generally speaking, matting products used in traditional solvent bornecoatings are not widely successful when used in powder coatingsprimarily because those products are not compatible with or designed tospecifically function within the mechanism in which powder coatings forma film. It has been found that while traditional matting products canreduce gloss, more often than not they cause film imperfections andother film failures.

More particularly, powder coatings are designed to flow during heating.As a result, the selection of polymers and crosslinkers for thosecoatings are based on molecular weight, degree of branching andfunctionality so that after application of the solid powder particles toa suitable substrate, usually a metallic substrate, the individualpolymer particles can collapse together and coalesce during heating.Crosslinking reactions occur subsequently, so that a smooth, continuousand hard film of good quality is formed. Particle collapse and flow ofthe initial dry powder structure can occur quite rapidly and a glossysurface is observed within a minute or two at normal cure temperatures,e.g., 120-200° C.

At the stage when the film first shows a glossy finish, surfaceroughness is still present. Indeed, the height roughness may be quitelarge at this stage. However, the slope of the roughness is expected todetermine the gloss, so that if the wavelength is large enough, theperception of a glossy surface will be provided. During further heatingand continuing coalescence, the slope of the surface roughness may stayapproximately the same and the film stays glossy.

On the other hand, if the powder coating particles do not havesufficient opportunity to flow, e.g., flow is physically impaired, atextured surface may develop, or alternatively, visually rough surfaceswith poor film properties may be obtained. Traditional matting productsmay be used to reduce the gloss of powder coatings to some extent, butas indicated above this approach is normally limited to low volumeamounts and when gloss levels above 60 units at 60° are acceptable. Eventhen, impairment of film properties may result.

Physical flow impairment is also regarded as occurring if the molecularweight of the binder polymer is too high, or if the functionality of thepolymer or crosslinker is too high. Particles sizes of the binderpolymer also can be large enough to impair coalescence and subsequentflow.

However, moderately hindered flow should permit the slope of the surfaceroughness to increase during heating following the stage of initial flowand coalescence so that a matt surface can be created from an initiallyglossy one, since at this stage, flow processes are still occurring.

Accordingly, and without being held to any particular theory, a suitablematting agent for powder coatings should be able to provide for anincrease in the slope of the surface roughness of the powder coatingduring film formation as a result of chemical reaction. Morespecifically, a suitable matting agent hinders coating flow after thepowder has formed the initial glossy state. This may occur by means ofmolecules having a suitable density and distribution of reactive groups.These methods can be classified as essentially chemical or reactive innature as opposed to the essentially physical or non-reactive methodsassociated heretofore with the use of typical fillers and waxes.

However, care should be taken not to introduce compounds that result ina high degree of flow inhibition or are so reactive that significantnetwork formation occurs too early in the curing schedule of the powdercoating, as this may negatively influence film appearance and filmproperties as described earlier. FIG. 3 shows linear viscoelasticproperties of a powder coating cured with crosslinking agents containingonly β-hydroxyalkylamide groups. Following an initial decrease in thephase angle as crosslinking reactions begin, at a temperature of 140° C.the phase angle starts to increase again indicating an increase influidity, before dropping again at 160° C. as the material solidifiesand chemical reactions go towards completion.

Without being held to a particular theory, this may arise as a result offree COOH or OH groups attacking the ester linkage proximally located bythe amide group, by transesterification, leading to a temporary decreasein molecule weight, prior to the final molecular weight build-up athigher temperatures as indicated by approach of the phase angle to 0°.This may explain why compounds with a large number ofβ-hydroxyalkylamide groups per molecular are nevertheless capable ofproducing glossy powder coating films of good quality.

This data therefore indicates that if the proportion ofβ-hydroxyalkylamide groups to total functional groups per molecule istoo high then matting will not be possible. On the other hand, thefunctionality content of the inventive composition minimizes that effectbecause not more than 50% of the total number of functional groups permolecule may be β-hydroxyalkylamide groups. The implication is thereforethat the invention is associated with maintaining sufficient flow andreactive capability to produce powder coating films with good appearanceand film properties but consistent with the powder coating film beingmatte. The invention can also avoid the need to adjust the ratio ofresin to crosslinker in the base powder coating formulation, which wouldalso be helpful in maintaining film properties insofar that dualfunctionality is intentionally built into a given compound.

The aminoalcohols and carboxylic acid compounds employed in preparingthe ester and ester-amide condensation products of this invention canvary and accordingly this invention offers a large number of ways toproduce the desired sometimes dual functionality of this invention.Accordingly, the compounds of this invention can even be combined withconventional β-hydroxyalkylamide crosslinkers of the types disclosed inpatents referred to above to obtained the desired dual functionality andthus offer additional compounds to control film properties (other thanmatte) of matted coatings.

The preferred embodiments, and modes of operation of the presentinvention have been described in the foregoing specification. Theinvention which is intended to be protected herein, however, is not tobe construed as limited to the particular embodiments disclosed, sincethey are to be regarded as illustrative rather than restrictive.Variations and changes, therefore, may be made by those skilled in theart without departing from the spirit of this invention. Further, anyrange of numbers recited in the specification or claims, such as thatrepresenting a particular set of properties, conditions, physical statesor percentages, is intended to literally and expressly incorporateherein any number falling with such range, including any subset rangesof numbers with a range so recited. The examples given below thereforeonly illustrate preparation of the matting compounds described hereinand tested in the particular powder coatings mentioned below in order tomerely illustrate gloss reductions of powder coatings by means of thechemistry discussed above.

SPECIFIC EXAMPLES

The powder coating employed is indicated below and represents a typicalepoxy-polyester coating. The matting compounds were added so as to givea volume fraction in the coating of around 0.05 in most cases, with theproportion of polyester and epoxy being simultaneously adjusted asneeded to accommodate the functionality of the matting compounds.

As a reference point, Ciba 3557, a commercially available reactivematting agent was used in the same way with simultaneous adjustment ofthe proportion of epoxy and polyester resins. Polyester-Primid powdercoatings were also employed.

Example 1

1 mole of Primid XL552 having four β-hydroxyalkylamide groups permolecule was reacted with 2.5 moles of 1,2,4,5Benzene-tetracarboxylicacid in the presence of silica in the solid state. In this instance,Primid XL552 contains terminal β-hydroxyalkylamide groups and isobtained as discussed earlier by reacting a diester, substantially thedimethyl ester of adipic acid, with two moles of diethanolamine.

Accordingly, 40.3 g of Primid XL552 from Rohm&Haas and 80 g of1,2,4,5Benzene-tetracarboxylic acid were dissolved in 53.8 g of water.41 g of (Syloid C807) silica gel having a pore volume of approximately 2cc/g was added and the mixture was stirred at room temperature for 1hour. The excess water was removed by heating at 120° C. withapplication of a vacuum to 300 mmHg whereupon the temperature was raisedto 150° C. and maintained for 4 hours to allow reaction to take place.

The acid value of the end product was low and did vary compared to thetheoretical value of 279 mgKOH/g. The acid values reported in thisExample and those that follow were measured using the following method:About 0.5 g of the sample product is added to 100 ml tetrahydrofuran(THF) and stirred for one hour under mild warming (maximum to 35° C.).The solution is titrated at room temperature with aqueous 0.1M KOHagainst a phenolphthalein indicator to a pink colored end point fromwhich the acid value AV can be calculated as AV=(5.61 *V)/S where V isthe volume in mis of KOH solution and S is the weight of the dry sample.The organic to inorganic ratio was 2.7:1 by weight. The presence ofbonded aggregates may explain the discrepancy in acid values. Thedensity of the final solid product was determined by Pykonometry to be1.57. This density, together with the theoretical acid value, was usedfor purposes of calculating powder coating formulations.

The product (Product A) was incorporated into a standard polyester-epoxypowder coating at a volume fraction addition level of 0.05. Thecomposition of the coating on a weight basis is given in the tablebelow. Polyester-Epoxy Powder Coating for Product A Component % byWeight Uralac P5071 (Polyester Resin) 32.79 Araldite GT7004 (EpoxyResin) 34.06 Kronos 2310 (Titanium Dioxide) 26.66 Product A 5.23 Byk365P (Flow Agent) 0.99 Benzoin (Flow and Degassing Agent) 0.27 100

The percentage addition of matting agent by weight was therefore 5.2%,3.8% of which arose from the organic constituent. The powder coating wasprepared and tested under the standard conditions discussed later below.

Example 2

The commercially available crosslinker Primid XL552 was again employedas a compound containing terminal β-hydroxyalkylamide groups. PrimidXL552 was reacted with the anhydride functionality of1,2,4-benzene-tricarboxylic acid anhydride to produce a substantiallymonomeric ester-amide containing 8 terminal carboxylic acid groups permolecule and combined with Pural 200 (γ-AlO.OH) alumina. The pore volumeof Pural 200 alumina is 0.6 cc/g.

Thus 29.67 g of Primid XL552 were charged to a reaction vesselcontaining N,N-dimethylacetamide (DMA) and after dissolution, 71.16 g ofbenzene-1,2,4 tricarboxylic acid 1,2-anhydride were added understirring. The amount of DMA was selected so that the final concentrationwas 25% by weight. The mixture was heated to 90° C. for 1 hour. The acidvalue was determined to be 452 mgKOH/g compared to the theoretical valueof 402 mgKOH/g. The method to determine acid value is expected to havean error of about ±5%.

The vessel was charged with 168.05 g of Pural 200 and after throughmixing, the contents of the reaction vessel were slowly added to 1 literof distilled water, preheated to 40° C. The precipitate was separated byfiltration and washed three times by reslurrying each time in 1 liter ofdistilled water preheated to 40° C. The final precipitate was dried at90° C. for 16 hours and pulverized. The acid value of the final productwas determined to be 100 mgKOH/g compared to the theoretical value of151 mgKOH/g.

Decomposition and removal of the organic component at 950° C. indicatedthat the percentage of organic compound was close to the theoreticalvalue of 38%. Bonded aggregates may therefore have formed, therebyaffecting acid value measurement. The density of the final solid productwas determined by Pykonometry to be 2.1 and this, together with thetheoretical acid value was used for purposes of calculating powdercoating formulations.

The product (Product B) was incorporated into a standard polyester-epoxypowder coating at a volume fraction addition level of 0.05. Thecomposition of the coating on a weight basis is given in the tablebelow. Polyester-Epoxy Powder Coating for Product B Component % byWeight Uralac P5071 (Polyester Resin) 35.74 Araldite GT7004 (EpoxyResin) 29.92 Kronos 2310 (Titanium Dioxide) 26.20 Product B 6.88 Byk365P (Flow Agent) 0.27 Benzoin (Flow and Degassing Agent) 0.99 100

The percentage addition of matting agent by weight was therefore 6.9%,2.6% of which arose from the organic constituent. The powder coating wasprepared and tested under the standard conditions discussed below.

Example 3

By an alternative method, a non-linear polymeric ester-amide withterminal carboxylic acid groups and only terminal amide groups wasprepared by transesterifying 4.5moles of dimethyl adipate with 1 mole oftrimethylolpropane, subsequent reaction of the remaining ester groupswith 6 moles of diethanolamine, followed by further reaction with 12moles of 1,2,4-benzene tricarboxylic acid anhydride. Thus, 10.3 g oftrimethylolpropane was melted at a temperature of 60° C. and charged toa reactor. 60.1 g of dimethyladipate was blended in followed by 0.1 g ofa transesterification catalyst.

Under a nitrogen atmosphere, the temperature was raised to 120° C. andthen again gradually to 150° C. and held there for a period of 4 hours.A vacuum of 300 mmHg was applied and held for a further four hours. Thedistillate had a refractive index of 1.3369, indicating methanol. Thereactor was subsequently charged with 48.4 g of diethanolamine and undera nitrogen atmosphere, heated at 120° C. for four hours. A vacuum of 300mmHg was applied and the resulting distillate had a refractive index of1.3358, indicating methanol.

176.8 g of 1,2,4-benzene tricarboxylic acid anhydride dissolved in 296 gof dimethylacetamide was added to the reactor and the mixture was heatedunder reflux for a period of four hours at 90° C. The acid value wasdetermined to be 399 mgKOH/g compared to the theoretical value of 377mgKOH/g.

The vessel was charged with 493 g of Pural 200 and after through mixing,the contents of the reaction vessel were slowly added to 2.5L ofdistilled water at room temperature. The precipitate was separated byfiltration and washed three times by reslurrying each time in 2.5L ofdistilled water. The final precipitate was dried at 95° C. for 16 hoursand pulverized. The acid value of the final product was determined to be77 mgKOH/g compared to the theoretical value of 125 mgKOH/g.

Decomposition and removal of the organic component at 950° C. indicatedthat the percentage of organic compound was at 33%, close to thetheoretical value of 38%. Bonded aggregates may therefore have formed,thereby likely causing the measured acid value to vary from thetheoretical acid value. The density of the final solid product wasdetermined by Pykonometry to be 2.04 and this, together with thetheoretical acid value was used for purposes of calculating powdercoating formulations.

The product was labeled product C and its behavior was assessed in astandard polyester-epoxy powder coating at a volume fraction additionlevel of 0.05. The composition of the coating on a weight basis is givenin the table below. Polyester-Epoxy Powder Coating for Product CComponent % by Weight Uralac P5071 (Polyester Resin) 38.11 AralditeGT7004 (Epoxy Resin) 28.51 Kronos 2310 (Titanium Dioxide) 26.60 ProductC 6.78 (2.6 organic) Byk 365P (Flow Agent) 0.28 Benzoin (Flow andDegassing Agent) 1.00 100

The percentage addition of matting agent by weight was therefore 6.8%,2.6% of which arose from the organic constituent. The powder coating wasprepared and tested under the standard conditions discussed below.

Example 4

To illustrate the effect of catalysts and co-reactants, the mattingcompound described in Example 1 and labeled product A, was tested incombination with tetrabutylphosphonium bromide according to theformulation given below. Polyester-Epoxy Powder Coating for Product Awith tetrabutylphosphonium bromide Component % by Weight Uralac P5071(Polyester Resin) 28.22 Araldite GT7004 (Epoxy Resin) 36.41 Kronos 2310(Titanium Dioxide) 26.86 Product A 5.27 Tetrabutylphosphonium bromide1.95 Byk 365P (Flow Agent) 0.99 Benzoin (Flow and Degassing Agent) 0.30100

As before, the percentage addition of matting agent arising from theorganic component amounted to 3.9%. The powder coating was prepared andtested under the standard conditions discussed below.

Example 5

As a further illustration of the effect of catalysts and co-reactants,the matting compound described in Example 3 and labeled product C, wasalso tested in combination with tetrabutylphosphonium bromide accordingto the formulation given below. Polyester-Epoxy Powder Coating forProduct C with tetrabutylphosphonium bromide Component % by WeightUralac P5071 (Polyester Resin) 33.14 Araldite GT7004 (Epoxy Resin) 30.41Kronos 2310 (Titanium Dioxide) 26.49 Product C 6.78Tetrabutylphosphonium bromide 1.92 Byk 365P (Flow Agent) 0.99 Benzoin(Flow and Degassing Agent) 0.30 100

As before, the percentage addition of matting agent arising from theorganic component amounted to 2.6%. The powder coating was prepared andtested under the standard conditions discussed below.

Example 6

As a further example of a non-linear polymeric ester-amide with terminalcarboxylic acid groups but containing a greater amount of amide groupsper molecule than in Example 3, 1 mole of hexahydrophthalic anhydridewas reacted with 1.2moles of diisopropanolamine and subsequently reactedwith 1.2 moles of 1,2,4-benzene tricarboxylic acid anhydride. In thisinstance, the material was prepared without combination with silica oralumina.

Thus 77 g of hexahydrophthalic acid was heated at a temperature of 45°C. and added to a reactor. 80 g of diisopropanolamine dissolved in 40 gof N-methylpyyrrolidone at the same temperature was subsequently blendedin. The temperature was raised to 90° C. and the components allowed toreact under reflux in a nitrogen atmosphere for 1 hour with constantstirring. Thereupon, a distillation head was fitted to the apparatus andthe temperature slowly raised to 160° C. Distillation was continued for3 hours, until an acid value of <2 mgKOH/g was attained indicatinggreater than 98% reaction.

The apparatus was converted back to reflux, 115.2 g of 1,2,4-benzenetricarboxylic acid 1,2-anhydride dissolved in 232 g ofN-methylpyrrolidone was added to the reactor and the mixture was heatedunder reflux for a period of four hours at 90° C. in a nitrogenatmosphere. The acid value was determined to be 270 mgKOH/g compared tothe theoretical value of 256 mgKOH/g.

The contents of the reaction vessel were slowly added in a continuousstream to 2.5L of distilled water at room temperature under intensestirring. The precipitate was separated by filtration and washed threetimes by reslurrying each time in 2.5L of distilled water. The finalprecipitate was dried at 35° C. for 16 hours under vacuum andpulverized. The acid value of the final product was determined to be 246mgKOH/g compared to the theoretical value of 256 mgKOH/g.

The product was labeled product D and its behavior was assessed in astandard polyester-epoxy powder coating together withtetrabutylphosphonium bromide. The composition of the coating on aweight basis is given in the table below. Polyester-Epoxy Powder Coatingfor Product D Component % by Weight Uralac P5071 (Polyester Resin) 32.88Araldite GT7004 (Epoxy Resin) 32.35 Kronos 2310 (Titanium Dioxide) 27.06Product D 5.19 Tetrabutylphosphonium bromide 1.04 Byk 365P (Flow Agent)0.99 Benzoin (Flow and Degassing Agent) 0.49 100

The powder coating was prepared and tested under the standard conditionsdiscussed below.

Example 7 Comparison 1

As a reference point, the commercially available product Ciba 3357 wastested in the standard polyester-epoxy powder coating at a volumefraction of 0.04. The formulation employed is given below. ReferencePolyester-Epoxy Powder Coating for Ciba 3357 Component % by WeightUralac P5071 (Polyester Resin) 27.06 Araldite GT7004 (Epoxy Resin) 40.81Kronos 2310 (Titanium Dioxide) 26.89 Ciba 3357 3.76 Byk 365P (FlowAgent) 0.98 Benzoin (Flow and Degassing Agent) 0.49 100

The commercially available product was therefore tested at a weightaddition level of 3.8%.

Example 8 Comparison 2

As a reference point, a standard unmatted polyester-epoxy powder wasprepared according to the formulation given below. UnmattedPolyester-Epoxy Powder Coating Component % by Weight Uralac P5071(Polyester Resin) 49.80 Araldite GT7004 (Epoxy Resin) 22.77 Kronos 2310(Titanium Dioxide) 27.42 Byk 365P (Flow Agent) 1.00 Benzoin (Flow andDegassing Agent) 0.28 100

Example 9 Comparison 3

As a reference point, a standard unmatted polyester-epoxy powder wasprepared containing tetrabutylphosphonium bromide according to theformulation given below. Unmatted Polyester-Epoxy Powder Coatingcontaining tetrabutylphosphonium bromide Component % by Weight UralacP5071 (Polyester Resin) 44.60 Araldite GT7004 (Epoxy Resin) 24.76 Kronos2310 (Titanium Dioxide) 27.37 Tetrabutylphosphonium bromide 1.98 Byk365P (Flow Agent) 0.99 Benzoin (Flow and Degassing Agent) 0.3 100

Example 10

As an alternative example of a non-linear polymeric ester-amide havingterminal carboxylic acid groups, 1 mole of hexahydrophthalic acid wasreacted with 1 mole of diethanolamine followed by reaction with 2 molesof cyclopentanetetracarboxylic acid in the solid state in the presenceof silica. Thus 61.67 g of hexahydrophthalic acid was melted at atemperature of 45° C. and added to a reactor. 42.1 g of diethanolaminewas subsequently blended in.

The temperature was raised to 70° C. and the components allowed to reactunder reflux in a nitrogen atmosphere for 1 hour with constant stirring.The product had an acid value close to the theoretical value of 217mgKOH/g. 50.5 g of the reaction product was dissolved in 200 g of water,followed by 95.9 g of cyclopentanetetracarboxylic acid and 88 g of a(Syloid C807) silica gel having a pore volume of approximately 2 cc/g.

The excess water was removed by heating at 120° C. with application of avacuum to 300 mmHg whereupon the temperature was raised to 150° C. andmaintained for 4 hours to allow reaction to take place. The acid valueof the end product was determined to be 225 mgKOH/g, about two-thirds ofthe theoretical value of 330 mgKOH/g. The organic to inorganic ratio was1.5:1 by weight. The presence of bonded aggregates may have caused themeasured acid value to vary from the theoretical acid value. The densityof the final solid product was determined by Pykonometry to be 1.57 andthis, together with the theoretical acid value was used for purposes ofcalculating powder coating formulations.

The product was labeled product E and was incorporated into a standardpolyester-primid powder coating at a volume fraction addition level of0.05. The composition of the coating on a weight basis is given in thetable below. Polyester-Primid Powder Coating composition for Product EComponent % by Weight Uralac P860 (Polyester Resin) 61.31 Primid XL 552(Crosslinker) 5.78 Kronos 2160 (Titanium Dioxide) 26.46 Product E 5.19Byk 365P (Flow Additive) 0.27 Benzoin (Flow and Degassing Additive) 0.99100

The percentage addition of matting agent by weight was therefore 5.2%,3.1% of which arose from the organic constituent. The powder coating wasprepared and tested under the standard conditions discussed below.

Example 11 Comparison 4

As a reference point, a standard unmatted polyester-primid powder wasprepared according to the formulation given below. UnmattedPolvester-Primid Powder Coating Component % by Weight Uralac P860(Polyester Resin) 69.21 Primid XL 552 (Crosslinker) 3.63 Kronos 2160(Titanium Dioxide) 27.16 Byk 365P (Flow Additive) 1.00 Benzoin (Flow andDegassing Additive) 0.28 100

Example 12 Gloss and Film Properties of Powder Coatings with InventiveMatting Agent

In all cases, the general procedure for preparing the powder mixtures ofthe above formulations was as follows. Polyester and epoxy resins orPrimid XK552 crosslinker as appropriate, titanium dioxide, flow anddegassing additives together with the matting compound and any otheradditives were charged in the desired amounts to a Prism Pilot 3premixer and mixed at 2000 rpm for 1 minute. Extrusion was carried outon a Prism 16 mm twin screw extruder with an outlet temperature of 120°C. The extrudate was broken up and milled on a Retsch UltracentrifugalMill to an average particle size of about 40μm. Sieving was employed toremove particles above 100 μm.

The white powder coatings were then applied to cold rolled steel testpanels (Q-Panel S412) by electrostatic spraying using a Gema PG1 Gun ata tip voltage of 30 kV. The coated panels were cured in an oven at 180°C. for 15 minutes and those panels having film thicknesses in the rangeof 60-80 μm were selected for testing.

Gloss was determined at 60° by means of a Byk Glossmeter. To assess theextent of chemical reaction following curing of the coatings, theresistance of the film to methyl ethyl ketone (MEK) was determined. Thisinvolved rubbing the powder coating film with a cloth soaked in MEK andthe resistance was expressed as the number of double rubs required underan approximately 1 Kg load before the underlying metal surface wasexposed.

Gardner Impact Testing (ASTM G1406.01) was carried out to assessflexibility. The painted side is facing down into the machine. The pointto first cracking and the point at which adhesion loss occurred were.determined. Adhesion loss following impact testing was assessed byapplying and removing sticky tape from the impacted region and decidingwhether portions of the coating had been removed or not. The results aregiven in TABLE 1 Table 1: Gloss levels at 60°, MEK resistance and ImpactResistance for various compounds added to a standard epoxy-polyesterpowder coating (Examples 1-9) or a standard polyester-primid powdercoating (Examples 10-11) and applied to cold rolled steel panels(Q-Panels S412) at a film thickness of 60-80 μm. Impact Impact GlossAppearance Cracking Adhesion Sample (60°) Visual MEK (inch · lbs) (inch· lbs) Example 1 34 Smooth >100 <4 20 Example 2 43 Smooth >100 10 40Example 3 43 Smooth >100 10 100 Example 4 7 Smooth * >100 55 >160Example 5 29 Smooth >100 20 >160 Example 6 24 Smooth >100 120 >160Example 7 50 Smooth 50 20 120 Comparison 1 Example 8 92 Slightorange >100 >160 >160 Comparison 2 peel Example 9 93 Slightorange >100 >160 >160 Comparison 3 peel Example 10 52 Smooth >100 <4 <4Example 11 95 Slight orange >100 >160 >160 Comparison 4 peel* Slight yellowing

Examples 1 to 6 demonstrate clear reductions in gloss with reasonable togood retention of film properties compared to Example 7 and to unmattedcoatings represented by Example 8.

Example 8 compared to Example 9, shows that addition oftetrabutylphosphonium bromide to the unmatted powder coating formulationalone has no effect on the gloss levels attained, whereas comparison ofExamples 1 and 3 with Examples 4 and 5 demonstrates that improvements inboth matting and film properties result when matting agents discussed inthis work are combined with such catalysts or coreactants.

Example 13 The Effect of Addition Level of the Inventive Matting Agent

To illustrate that gloss values may be adjusted by varying the additionlevels of the inventive matting agent, the inventive condensationproduct represented by Example 6 was tested in an epoxy-polyester powdercoating together with a matt activator as before, but at differentaddition levels of the condensation product, keeping the ratio of thecondensation product to matte activator constant. The proportion ofpolyester and epoxy resins were simultaneously adjusted to accommodatethe functionality of the matting compound. The formulations prepared areshown in the table below, where all entries are in percent by weight.Component 1 2 3 Uralac P5071 49.07 38.62 32.88 Araldite GT7004 22.4329.22 32.35 Kronos2310 27.02 27.01 27.06 Product D — 3.06 5.19 TBPB —0.61 1.04 Byk 365P 0.99 0.99 0.99 Benzoin 0.49 0.49 0.49 100 100 100TBPB = Tetrabutylphosphonium bromide

The results obtained for each of the four formulations are shown inTable 2. TABLE 2 The effect of addition level of the inventive mattingagent on matting and film properties, where the ratio of thecondensation product to matte activator is held constant Impact ImpactGloss Appearance Cracking Adhesion Number (60°) Visual MEK (inch · lbs)(inch · lbs) 1 92 Slight Orange >100 >160 >160 Peel 2 58Smooth >100 >160 >160 3 24 Smooth >100 120 >160

Thus, a decrease in gloss occurs with an increasing proportion ofmatting compound, coupled with good retention of film properties,demonstrating a further desirable feature of the matting compoundsdiscussed above.

1. Condensation product comprising (a) at least one ester-amide (b)optionally, at least one β-hydroxyalkylamide functional group and (c) atleast one reactive functional group other than (b) wherein (b), ifpresent, constitutes no more than 50% of the total (b) and (c) on a molebasis.
 2. Condensation product according to claim 1 wherein (c) isselected from carboxyl, isocyanate, epoxide, hydroxyl and alkoxy silane.3. Condensation product according to claim 1 wherein the condensationproduct contains an ester amide selected from the group of monomericester-amides, oligomeric ester amides and polymeric ester-amides. 4.Condensation product according to claim 1 wherein (b) is

R¹, R², R³ and R⁴ may, independently of one another, be the same ordifferent, H, straight or branched chain alkyl, (C₆-C₁₀) aryl or R¹ andR³ or R² and R⁴ may be joined to form, together with the combinations, a(C₃-C₂₀) cycloalkyl radical; m is 1 to 4 and R⁵ is

and R¹, R², R³, R⁴ and m as defined above.
 5. Condensation productaccording to claim 4 wherein (c) is selected from carboxyl, isocyanate,epoxide, hydroxyl and alkoxy silane.
 6. Condensation product accordingto claim 1 wherein the condensation product's functional groups consistessentially of (c).
 7. Condensation product according to claim 1 havinga total functionality on a mole basis in the range of about 4 to about48.
 8. Condensation product according to claim 1 having a functionalityon a mole basis of at least
 8. 9. Condensation product according toclaim 1 having a total functionality on a mole basis in the range ofabout 8 to about
 24. 10. A composition comprising condensation productaccording to claim 1, wherein said composition comprises inorganicparticulate.
 11. Composition according to claim 10 wherein the inorganicparticulate comprises inorganic oxide.
 12. Composition according toclaim 10 wherein the inorganic particulate comprises silica or aluminumoxide.
 13. Composition comprising condensation product according toclaim 1, wherein said composition further comprises a matte activator.14. Composition according to claim 13 wherein the matte activator is ahydrocarbyl phosphonium salt.
 15. A powder coating compositioncomprising condensation product according to claim 1, wherein saidcomposition further comprises reactive binder.
 16. A powder coatingcomposition according to claim 15 wherein the reactive binder comprisesa polymer selected from the group consisting of epoxy, epoxy-polyester,polyester-acrylic, polyester-primid, polyurethane and polyacrylic.
 17. Apowder coating composition according to claim 15 further comprisinginorganic particulate.
 18. A powder coating composition according toclaim 17 wherein the inorganic particulate comprises inorganic oxide.19. A powder coating composition according to claim 17 wherein theinorganic particulate comprises silica or alumina.
 20. A powder coatingcomposition according to claim 15 further comprising matte activator.21. A powder coating composition according to claim 20 wherein the matteactivator is a hydrocarbyl phosphonium salt.
 22. A method of matting apowder coating comprising adding inorganic particulate and acondensation product according to claim 1 to a powder coatingcomposition.
 23. A method according to claim 22 wherein the inorganicparticulate is inorganic oxide.
 24. A method according to claim 22wherein the inorganic particulate comprises silica or aluminum oxide.25. A method according to claim 22 wherein a matte activator is added tothe powder coating composition in addition to the inorganic particulateand the condensation product.
 26. A method according to claim 25 whereinthe matte activator is a catalyst/coreactant.
 27. A method according toclaim 22 wherein the powder coating comprises a reactive binder andcomprises a polymer selected from the group consisting of epoxy, epoxypolyester, polyester acrylic, polyester primid, polyurethane, andpolyacrylic.
 28. A method according to claim 26 wherein thecatalyst/coreactant is a phosphonium salt of the formula

wherein each R is independently a hydrocarbyl or inertly substitutedhydrocarbyl group, Z is a hydrocarbyl or inertly substituted hydrocarbylgroup and X is any suitable anion.
 29. A method according to claim 28wherein the catalyst/coreactant is a hydrocarbyl phosphonium salt.